Mounting and latching means for annunciator lamp housing panels



Jan. 30, 1962 w. c. ARRASMITH 3,019,428

MOUNTING AND LATCHING MEANS FOR ANNUNCIATOR LAMP HOUSING PANELS Filed May 17, 1960 2 Sheets-Sheet 1 JO Mv Jan. 30, 1962 w, c. ARRASMITH 3,019,428

MOUNTING AND LATCHING MEANS FOR ANNUNCIATOR LAMP HOUSING PANELS Filed May 17, 1960 2 Sheets-Sheet 2 ares Patent 3,019,428 Patented dan. 30, 1962 3,019,428 MOUNTING AND LATCHING MEANS FOR AN- NUNCIATOR LAMP HOUSING PANELS William C. Arrasmith, Beverly Hilis, Calif., assigner to Radar Relay, Inc., Santa Monica, Calif., a corporation of California Filed May 17, 1960, Ser. No. 29,644 9 Claims. (Cl. 340-381) The present invention relates to equipment and apparatus for monitoring a plurality of conditions, and it is more particularly concerned with an improved annunciator unit for providing visual indications at a central station of the happenings of monitored occurrences at different remote points.

Anuunciator systems and equipment are generally well known. One type of annunciator system, for example, is disclosed and claimed in Patent 2,887,677, which issued May 19, 1959, in the name of the present inventor. The annunciator system described in the patent includes electrically energized lamps which are mounted in individual lamp housings, which, in turn, are supported on a central control panel. Appropriate circuitry is provided for connecting the lamps to different sensing elements. These sensing elements are located at difterent points remote from the central control panel, and they serve to indicate the occurrence of different conditions which are to be monitored by the system. Each of the sensing elements in the system described in the patent may include, for example, a pair of normally open electric contacts. These sensing elements are constructed to respond to the occurrence of the different monitored conditions, and when any one of the monitored conditions actually occurs, the electric contacts in the corresponding sensing element close.

The electrically energized lamps used in the different annunciator units are preferably mounted in pairs in the individual lamp housings so that the indication will not be completely lost should one of the lamps burn out. Each of the lamp housings in the apparatus described in the patent has a front surface which is suitably inscribed. These inscriptions are not normally visible, however, they do become clearly visible when the corresponding lamp housing is illuminated by the energizing of its lamps. The inscriptions on the iront surface of the individual lamp housings may read, for example Air Oli, Empty, Parachute Released and so on. In each instance, the illuminated inscription serves to identify the particular condition monitored by its associated sensing element, and which condition has actually occurred to cause the contacts in its associated sensing element to close.

Patent 2,934,752, which issued April 26, 1960, in the name of the present inventor also discloses and claims an improved type of annunciator system and apparatus. The annunciator system disclosed and claimed in the latter patent is also of the general type described above` ln the apparatus described in the latter patent, the control circuits and elements associated with each of the diiferent lamp housings are positioned in a small rectangular shaped capsule. The corresponding translucent lamp housing is constructed to plug into the front edge of the particular capsule. These capsules are constructed so that they may conveniently be mounted on top of one another to be held in an assembled stacked relationship. The stacked capsules are then mounted on a central control panel, and the corresponding translucent lamp housings are plugged into respective ones of the front edges of the capsules. TheA lamp housings are so plugged into the front edges of the capsules from the front of the central control panel and through appropriate openings in the panel.

Copending application 825,461, which was liled July 7, 1959, and which has now issued as Patent 2,959,774, is also concerned with annunciator apparatus similar to that disclosed and claimed in Patent 2,934,752. In the copending application, however, the construction is such that the translucent lamp housings can be mounted tlush with the front surface of the control panel. This liush mounting of the lamp housings is advantageous, for example, in the cockpit of an aircraft where projecting elements can be dangerous and are a nuisance. Moreover, the method whereby the different translucent lamp housings may be removed is such that these housings can be supported directly adjacent one another to occupy a minimum of space on the control panel. This is most important in practically all applications of units of this type because space is usually at a premium.

in accordance with the teaching of the copending application 825,461 referred to above, the individual lamp housings may be positioned closely adjacent to one another on the control panel andV yet be conveniently removable on an individual basis and without interference from the adjacent housings. This removal of any one ofw the lamp housings is achieved merely by depressing the lamp housing to be removed and then releasing it. The subsequent release of the larnp housing causes the associated latching mechanism, in the manner described in the copending application, to displace the particular lamp housing to a position in which it protrudes out from the plane of the control panel and out from the front surfaces of the other lamp housings. This places the particular lamp housing in a position in which it can be quickly and easily removed from the assembly. Such removal is usually desirable so that burned out lamps may be replaced.

The present invention is also directed to the flush type of annunciator equipment such as is disclosed and claimed in the copending application 825,461. An important object of the Present invention is to provide such annunciator apparatus which is constructed in an improved manner to be rugged in its construction.

A further object of the invention is to provide such an improved type of annunciator apparatus in which each flush type lamp housing may be positively actuated between a released condition and a latched condition, and in which each lamp housing is firmly and positively held on its associated capsule when in the latched condition,

Yet another object of the invention is to provide such an improved annunciator unit in which the associated lamp housing may be caged to its corresponding capsule so as to prevent the removal and the likelihood of subsequent erroneous replacement of the lamp housing in the wrong capsule. `It is Obviously rnost important that each inscribed lamp housing be plugged into the proper capsule, or its inscriptions will not properly identify which monitored condition has actually occurred.

ln the embodiment of the invention to be described, the individual translucent lamp housings each has an elongated plug member extending from it and into a hole in the front edge of the associated capsule. The capsule is provided with an apertured upstanding support member which is spaced inwardly from the front edge of the capsule and which receives the plug member. The construction is such that the plug member slides in the support member as the lamp housing is moved between its latched and its released position. This provides a positive support for the plug because it is slidably supported at spaced points by the front edge of the capsule and by the apertured supporting member. This, in turn, assures that when the lamp housing is moved between its released and latched condition, such motion will vproceed smoothly along a guided path.

The construction described briefly in the preceding acreage 'paragraph is also advantageous when it is desired to cage the lamp housingto the capsule, for the reasons described above. The caging vmay be achieved by the simple provision of a stop Imember at the extremity of the plug and on the opposite side of the supporting member. The stop member is made large enough so 'that it 'cannot pass through the aperture in the apertured support member. Alternatively, and as `will be described in a second embodiment of the invention, the stop member and the aperture in the support member may have a mating configuration. These configurations may be such that the stop member will pass through the aperture only for a particularl angular position of the plug. This causes the lamp housing to be caged on its associated capsule, but it permits 'the lamp housing to be removed if so desired by turning the plug to a particular angular position. v

The features of the invention which are believed to be new are set forth in the claims. Theinvention itself, however, together with further objects andv advantages, can best be understood by reference to thefollowing description when taken in conjunction with the accompanying drawings, in which:

FIGURE lis a rear perspective view of a plurality of 'capsulesassembled in a stacked condition and mounted on a control panel, each of the illustrated capsules containing circuitry and` control elements for electrically energized lamps which are contained in a corresponding plurality of lamp housings whichV are mounted on the different capsules in accordance ,with the concepts of the invention;

FIGURE 2 is a front view of the panel of FIGURE l to show the Afront faces of thedilerent lamp housings and but with the lamp housing released from its latched condition so as to permit the replacement of lits electrically energizedlamps;

FIGURES 5, ,6,V 7 and 8 are fragmentary schematic illustrations of a latching and support mechanism constructed in accordance with the concepts of the invention and which serves to releasably support the lamp housing on its associated capsule, these views illustrating subsequently how the lamp housing may be unlatched by depressing it inwardly toward the front edge of the capsule and by subsequently releasing it;

FIGURE 9 is a top plan view of a second embodiment of the invention in which the lamp housing is normally caged with respect to its associated capsule, but which may be uncaged by turning it and its associated plug member to a particular orientation; and

FIGURE l0 is a view substantially on the line lill0 of FIGURE 9, the latter view showing the mating configuration between a stop member on the plug member in FIGURE 9 and an aperture in a support member in FIG URE 9 to permit the stop member to be drawn through the aperture in the plug member when the plug member has a particular orientation.

As stated previously and as described in the abovementioned Patent 2,934,752, the control circuit and elements for each pair of electrically energized lamps in the system may be individually housed in a separate capsule, and the translucent annunciator member to be illuminated by the energizing of the particular pair of lamps is supported on one edge of the capsule in a manner to be described. Such capsules are designated 10 in FIGURE 1, a stack of similar `annunciator capsules being illustratedin FIGURE 1.

The annunicator capsules 1t) are held together in a stacked condition by a plurality of bolts I4 which extend through the entire stack and which have appropriate nuts threaded to their extremities to hold the stack of capsules in an assembled condition. The stack of capsules is supported on the rear face of a control panel 16 by means of a plurality of screws, such as screws 18. The individual capsules may be spaced rearwardly from the rear face of the control panel lo by a plurality of spacer members 2@ which may be inserted between the leading edge of each of the capsules 10 and the rear face of the panel 16.

Each of the capsules yl0 includes a movable member 2,2 associated with it. As shown in FIGURES l and 2, the movable members 22 may have a generally elongated rectangular configuration, and they are received by corresponding openings in the panel 16 and are supported on the front edge of their respective vcapsules 10 in a 'manner to be described. p

As shown in FIGURE 2, for example, each of the movable members 22 has suitable inscriptions formed on its front face. These inscriptions identify the particular hazardous condition monitored by that particular movable member. Whenever the particular hazardous condition actually occurs, and in a manner to be described, the resulting closure of a pair of contacts in a sensing element causes a corresponding pair of electrically energized lamps to illuminate a corresponding one of the movable members 22. For this purpose, the movable members are formed of a translucent'material, and they serve as housings for the electrically energized lamps.

As shown, for example, in FIGURES 1 and 3, the movable members 22 are supported by their corresponding capsules 10 in positions such that their front faces are flush with the frontface of the supporting panel 16. This, as mentioned above, is convenient in that it not only removes the undesirable condition of having projecting elements in a cockpit, for example; but in addition the improved latching mechanism of the invention permits the different movable members 22 to be mounted closely adjacent one another and yet be removed in a simple manner without interference from the adjacent movablev members, as will be explained.

As noteabove, each of the capsules 10 contains the For this purpose, each of the capsules has a pluralityV of terminals designated 28A, 25B, 28C, 28D and 28E mounted on its rear edge, and each of the capsules has an additional terminal 29 on its rear edge. The terminals 23A of all the capsules in the stack are connected together, as shown in FIGURE l. Likewise, all the terminals 28B are connected together, as are the terminals 28C, 28D and 28E.

The respective terminals 29, on the other hand, are connected to different sensing elements in the area being monitored by the unit.

As illustrated, for example, in FIGURES 3 and 4, each capsule 10 includes a pair of electric lamp receptacles 24 mounted on its leading edge. The receptacles l2d may be of any known physical construction, and they serve to receive a corresponding pair of electric lamp sockets 25. The lamp sockets 25 are mounted on the movable member 22 and protrude outwardly from the rear face of the movable member in respective axial alignment with the receptacles 24. The sockets 25 may also be of any known physical construction and coniiguration, and they serve to support a corresponding pair of electric lamps 26 in a position so that the lamps 26 extend into the translucent member 22 to illuminate the front face of the movable member and the inscriptions on that face.

It will be observed that the movable member 22 is normally positioned, as shown in FIGURES l and 2, in

the opening in the panel 16 so that its front surface is tlush with the front surface of the panel 16. When the movable member is in its normal position, the lamp sockets 25 extend into respective ones of the receptacles 24 so that an electric energizing circuit may be completed to the lamps 26. This circuit may be of the type described in Patent 2,934,752 referred to above, and it provides for the energizing of the lamps 26 upon the happening of the condition monitored by the particular annunciator capsule.

As best shown in FIGURE 4, an elongated plug member 30 is mounted on the movable member 22 and extends outwardly from the rear face of the movable member through an aperture in the leading edge of the capsule 10. The movable member 22 is fastened to the plug 30 by means of a hinge assembly 32. This hinge assembly permits-the movable member 22 to be turned down when in the extended position shown -in FIGURE 4. This facilitates the removal and replacement of the lamps 26.

An upstanding guide and support member 34 is fastened to the bottom of the capsule in a position spaced from and parallel to the leadingv edge of the capsule. This guide member has an aperture extending through it in axial alignment With-,the-aperture in the leading edge of the capsule whichfreceives the plug 3,0. This permits the end of the plug to extend through the aperture in the guide member 34. The arrangement is such that the movable member 22 may be conveniently moved from the extended position of FIGURE 4 to the normal position of FIGURE 3 inV a smooth and unimpeded manner. As the movable member is so moved between the two positions, the plug 30 moves in a guided manner through the aligned apertures in the front edge or" the capsule 1th and in the guide member 34. When the movable member 22 is in the normal position of FIGURE 3, the engagement of the sockets in the corresponding receptacles 24 holds the hinged movable member 22 in a position such that its front face is parallel with the front of the panel 16.

A coil spring 36 is mounted coaxially with the plug member 30. This coil spring engages the rear face of the movable member 22 and the front of the leading edge of the capsule It?. This spring serves to bias the movable member 22 outwardly from the panel -16 when it is released, as will be explained.

The elongated plug member has a rst shoulder portion 3S formed in it which faces the movable member 22. This shoulder portion is positioned intermediate the ends of the plug 30. A cylindrical member 40 is slidably mounted on the plug 30 adjacent the shoulder portion 3S. This cylindrical member has an internal diameter having an upper portion which is greater than the outer diameter of the shoulder portion 30 and having an inner shoulder, and the cylindrical member has an outer diameter which is `less than the diameter of the aperture in the leading edge of the capsule 10. This permits the cylindrical member 40 to slide freely along the plug member 3i) over the shoulder portion 38, and it also permits the cylindrical member 40 to be drawn through the aperture in the leading edge of the capsule 1b from the position shown in FIGURE 3 to the position shown in FIGURE 4 as the shoulder portion 38 engages the inner shoulder of the cylindrical member 40.

The plug member 3b has a second shoulder portion 42 adjacent the end or" the cylindrical member 41) and facing the shoulder portion 38. The shoulder portion 42 has a diameter greater than the inner diameter of the cylindrical member 4%, and it serves to engage the end of the cylindrical member 49 and force the cylindrical member into the housing when the movable member 22 is moved from the position of FIGURE 4 to the position of FIGURE 3.

A resilient jack 44 is mounted in the capsule 10 between the guide member 34 and the leading edge of the capsule 10. This jack is supported on the leading edge of the capsule 10 by a pair of nuts 45, and these nuts may also serve to mount the receptacles 24 on the leading edge of the capsule. The resilient jack 44 includes a first resilient arm 46 which extends to one side of the plug 3i), and it includes a second resilient arm 48 which extends to the other side of the plug. These resilient arms are shaped so that Jwhen the movable member 22 is moved inwardly from the position of FIGURE 4 to the position of FIGURE 3, the resilient arms 46 and 48 engage the shoulder portion 38 at diammetrically opposite positions to hold the movable member 22 in the position of FIGURE 3 and in a latched condition against the bias force of the spring 36.

The extremity of the plug 30 may be provided with a stop member 50 lwhich has a diameter greater than the diameter of the aperture in `the guide 34. This stop member 50 serves to cage the movable member 2 2 with respect tothe capsule 10. When the movable member is moved to the position of FIGURE 4, the lamps 26 may bev replaced conveniently, as mentioned above. However," the movable member cannot normally be removed -trom its associated capsule 10, because of the stop member 50. This stop member limits the forward travel of theplug 30. 'Ihis caging of the movable member 22 with the capsule 10 is important because it eliminates the likelihood of the movable member 22 being associated with the Wrong capsule 10. Should that occur, the inscriptions on the movable member 22 would serve as an erroneous indication of the monitored condition.

The manner in which the latching mechanism of FIGURES 3 and 4 operates when it is desired to release the movable member 22 is shown by the fragmentary schematic diagrams of FIGURES 5-8.

The illustration of FIGURE 6 shows the movable member 22 in its position as normally engaged by the jack 46 and held in place on the leading edge of its corresponding capsule 10. When it is desired to release the movable member, the member is depressed inwardly towards the capsule 10 as shown in FIGURE 7. This causes the cylindrical member or collar'40 to be moved by the shoulder portion 42 into the jack 44 and spread the arms 46 and 48 vof the jack so as to disengage the shoulder portions 38 ofthe plug from the jack. Then, when the movable member 22 is subsequently released, and as shown in FIGURE 8, the resilient spring 36 biases the movable member 22 outwardly from. the capsule 10 to withdraw the vshoulder portion 38 of the plug 30 down into the cylindrical member 40. The movable member 22 is now displaced outwardly from the plane of the front surface of the panel 16 in a position such that it may be moved outwardly to the position of FIGURE 5.

The cylindrical member 40 may be provided with a peripheral groove 49a near its forward extremity, and the arms 46 and 4S of the resilient jack 44 engage this groove with a slight retaining pressure when the cylindrical member is moved into the jack.

As mentioned above, it is now possible to move the displaced movable member 22 from the position shown in FIGURE 8 to the position shown in FIGURE 5. When the movable member 22 is in the position of FIGURE 5, and as noted above, it may be hinged downwardly to permit the convenient removal and replacement of the lamps 26.

The embodiment of the invention shown in FIGURES 8 and 9 is generally similar to the embodiment of FIGURES 3 and 4, and like elements have been identied by the same numerals. However, in the embodiment of FIGURES 8` and 9, the stop member 50 has been replaced by a stop member 60. The aperture through `the guide member 34 in the latter embodiment is designated 62, and this aperture has a configuration such that the stop member 60 may pass through it when the plug 30 has a particular angular orientation with respect to the guide member 34. This latter embodiaora-tee meut permits the unit to function as described above with the movable member Y22 being caged with respect to its corresponding capsule by means of the stop member Gt). However, under some circumstances it may be desirable to remove the movable member 22 completely. This `can be achieved by turning the movable member until the plug 36 has a particular orientation with respect to the guide 34. This orientation is such `that the stop member 60 may pass freely through the aperture 62 to permit the plug 30 and the assembly of the movable member 22 to be withdrawn completely vfrom the capsule 1).

The invention provides, therefore, an improved yassembly of the annunciator type. The improved assembly of the present invention includes a capsule 4and `an associable movable lamp housing member. The lamp housing 'member is supported in an improved manner to be guided 'along an Vestablished path between its latched condition and its extended condition. The assembly is constructed so that the movable Amember is securely latched to the lamp housing when in its normal condition, and in which the movable member Ymay be quickly and readily unlatched merely by depressing it inwardly and then releasing it. The'invention also provides an improved manner whereby the m'ovableymembe/r'is caged to its associated capsule for the described reasons.

In the second embodiment of the invention, the movable member and its associated components may be removed from the capsule merely by turning it to a particular orientation.

p l. An assembly for use in an electrical system including: a capsule-like housing for supporting electrical cireuitry and components having a plurality of walls including Van end w-all with a first aperture formed therein, a support and guide member positioned in said housing in spaced relationship with said end wall thereof and having a second aperture in axial alignment with said first aperture, a movable member, an elongated plug member having a shoulder portion formed therein and mounted on the movable member and projecting from the movable member into said first and second apertures to be Slidable therein and supported at spaced points by said front wall and by said support `and guide member, a resilient jack mounted in said housing in alignment with the irst and second apertures to engage the shoulder portion of said plug member and thereby hold the movable member on the housing, and means mounted on said plug member for releasing the shoulder portion thereof from said resilient jack when the movable member is moved in the direction of said end Wall 4of the housing.

2. An assembly for use in an electrical system including: a capsule-like housing for supporting electrical circuitry and components having a plurality of Walls including an end Wall with a first aperture formed therein, a support and guide member positioned in said housing in spaced relationship With said end Wall thereof and having a second aperture therein in axial alignment With said first aperture, a movable member, an elongated plug member having a first shoulder portion formed therein intermediate the ends thereof and mounted on the movable member and projecting from the movable member into said first and second apertures to be slidable therein and supported at spaced points by said front Wall and by said support and guide member, a resilient jack Amounted in the housing between said support member and said end Wall of the housing in a position to engage the rst shoulder portion of -said plug member and thereby hold the movable member on the housing, and a cylindrical member slidably supported on theplug adjacent said first shoulder portion thereof, and said plug member having a second shoulder portion formed therein for forcing the cylindrical member into the jack to disenga'ge the first Ashoulder portion of the plug from the jack when the movable member is moved in the direction of said end wall of the housing.

3. The combination defined in claim 2 `and which includes a stop member mounted on the extremity of the plug member remote from the movable member, to prevent said extremity or" the plug member from being drawn through said second aperture so as to cage the movable member on the housing.

4. The combination defined in claim 2 and in which said second `aperture has a particular conguration, and which includes a stop member mounted on the extremity of the plug member remote from the movable member, said stop member having a particular conguration with respect to the particular conguration of said second aperture to prevent said extremity of the plug member from being drawn through said second aperture and thereby cage the movable member on the housing except when said plug member is turned to a particular angular position in said support member.

5. An assembly for use in an electrical indicating system including: a capsule for supporting electrical circuitry and components `and having a plurality of Walls including an end wall with a first aperture formed therein, an opstanding support `and guide member positioned in said capsule in spaced parallel relationship with said end wall thereof and having a second aperture therein in axial alignment with said first aperture, a translucent lamp housing having inscriptions formed on a front face thereof,- an elongated plug member having a rst shoulder portionrformed therein intermediate the ends thereof and mounted on` said lamp housing and projecting therefrom into 'said first yand second apertures to be slidable therein and supported at spaced points by said front wall and by said support and guide member, a resilient jack mounted in the capsule between said support and guide member and said end wall of the capsule in a position to engage the first shoulder portion of said plug member and thereby hold the lamp housing in a latched condition on the capsule, a cylindrical member slidably mounted on the plug adjacent said first shoulder portion thereof and having an inner diameter greater than the outer diameter of said first shoulder portion of the plug and having `an outer diameter less than the diameter of said rst aperture, said plug member having a second shoulderV portion formed thereon adjacent an end of the cylindrical member to engage such end and force the cylindrical member into the jack so as to disengage the rst shoulder portion of the plug from the jack when the lamp housing is moved in the direction of said end wall of the capsule, and a coil spring supported on said plug between said end wall of the capsule and the lamp housing to retract the plug member from the jack when the first shoulder portion of the plug member is disengaged from the jack by said cylindrical member.

6. The combination dened in claim 5 and Which includes hinge means yfor attaching said lamp housing to said plug member to permit said lamp housing -to be turned -angularly with respect to the axis of said plug member so as to facilitate the removal and insertion of lamps in the lamp housing.

7. An assembly for an electrical indicating system including: a capsule for supporting electrical circuitry and components having a plurality of Walls including an end Wall With a first `aperture formed therein, electric socket means mounted on the end wall and electric circuitry positioned in said capsule and connected to said socket means, an upstanding support and guide member positioned in said capsule in spaced parallel relationship with said end wall thereof and having a second `aperture therein in axial alignment with said first aperture, a translucent lamp housing having inscriptions formed on a front face thereof and incuding means for supporting at least one electric lamp therein, said supporting means engaging said electric socket means when said lamp housing is supported in a latched condition on said capsule,

9 an elongated plug member having a first shoulder portion `formed therein intermediate the ends thereof and mounted on said lamp housing and projecting therefrom into said rst and second apertures to be slidable therein and supported at spaced points by said front wall and by said support and guide member, a resilient jack mounted in the capsule between said guide member and said end wall of the capsule in a position to engage the rst shoulder portion of said plug member and thereby hold the lamp housing in a latched condition on the capsule, a cylindrical member slidably mounted on lthe plug `adjacent said first shoulder portion thereof and having an inner diameter greater than the outer diameter of said first shoulder portion thereof and having an outer diameter less than the diameter of said first aperture, said plug member having a second shoulder portion formed thereof adjacent an end of the cylindrical member to engage said end of the cylindrical member and force the cylindrical member into the jack so as to disengage the first shoulder portion of the plug from the jack when the l-amp housing is moved in the direction of said end wall of the capsule, and a coil spring supported on said plug between the end wall of the capsule and the lamp housing to retract the plug member from the jack when the first shoulder portion of the plug member is disengaged from the jack by said cylindrical means.

8. The combination defined in claim 7 and which includes a stop member mounted on the extremity of the plug member remote from said lamp housing to prevent said extremity of the plug member from being drawn through said `second aperture so as to cage said lamp housing on said capsule.

9. The combination defined in claim 7 and in which said jack includes first rand second resilient `arms mounted on said end wall of the capsule and extending into the capsule on opposite sides of the plug member and in inclined relations-hip therewith, said resilient arms having end portions adapted to engage the first shoulder portion of the plug when said lamp housing is in said latched condition on the capsule.

References Cited in the Ile of this patent UNITED STATES PATENTS 780,417 Euphrat Jan. 17, 1905 1,866,326 Stevens July 5, 1932 2,959,774 Arrasmith Nov. 8, 1960 FOREIGN PATENTS 132,667 Australia June 2, 1949 

